1. Field of the Invention
The present invention relates to a sample preparation device which prepares a measurement sample from cells collected from a subject, a cell analyzer which analyzes the prepared sample, and a filter member for preparing the measurement sample.
2. Disclosure of Related Art
To date, there have been known cell analyzers which analyze cells contained in a biological sample collected from a living body. For example, there is known a cell analyzer which measures, by use of a flow cytometer, epidermal cells contained in a sample collected from the uterine cervix of a subject and which determines the state of advancement of canceration based on the result of the measurement.
Such a cell analyzer analyzes individual cells. Thus, in order to increase the accuracy of the analysis, it is desirable that the number of cells being an analysis target is larger. For example, there is known a sample preparation device that can increase the concentration of cells contained in the sample, thereby being able to increase the number of cells being the analysis target while suppressing the amount of the sample.
This sample preparation device includes: a storage chamber whose upper face is open and which stores a sample therein; a cylindrical piston which is inserted in this storage chamber and whose lower end face has a filter mounted thereto; an aspiration tube which aspirates a liquid that has entered the piston through the filter; and a stirrer disposed in a bottom portion of the storage chamber. In a step of concentrating a sample, first, the sample is put into the storage chamber, and then, the piston is inserted into the storage chamber until the filter is immersed in the sample. At this time, liquid that has leaked into the piston is aspirated by the aspiration tube, to be removed from the storage chamber. Cells being the analysis target do not pass through the filter and attach to the lower face of the filter. The cells attached to the lower face of the filter are removed from the filter, by the stirrer being driven as appropriate. As a result, the sample having an increased concentration of cells being the analysis target remains in the storage chamber.
However, in this sample preparation device, liquid that has leaked into the piston in association with insertion of the piston into the storage chamber is discharged by use of the aspiration tube. Thus, it is difficult to completely aspirate the liquid in the storage chamber. This may cause a large amount of cells other than cells being the analysis target to remain in the storage chamber. In addition, with this sample preparation device, in order to perform the process of concentrating cells being the analysis target, the piston needs to be moved up and down many times in the storage chamber. Thus, the concentrating process may take time.